Additives for oil compositions

Abstract

An additive composition comprises at least one polyoxyalkylene compound and at least one ethylene polymer, wherein the at least one ethylene polymer, in addition to units derived from ethylene, comprises units of the formula (I): and optionally, units of the formula (II): wherein each R 1 group independently represents hydrogen or methyl; wherein each R 2 group independently represents an alkyl group having 5 or more carbon atoms; wherein each R 3 group independently represents hydrogen or methyl; wherein each R 4 group independently represents an alkyl group having between 1 and 4 carbon atoms; wherein the proportion of units of formula (I) in the ethylene polymer is between 16 and 30 mol %; and wherein the total proportion of units of formula (I) and formula (II) in the ethylene polymer is between 19 and 30 mol %. The composition is particularly suitable for improving the low temperature properties of fuels having sharp distillation tails and low final boiling points.

1 . An additive composition comprising at least one polyoxyalkylene compound and at least one ethylene polymer, wherein the at least one ethylene polymer, in addition to units derived from ethylene, comprises units of the formula (I):  
     
       
         
         
             
             
         
       
       and optionally, units of the formula (II):  
       
         
           
           
               
               
           
         
       
       wherein each R 2  group independently represents hydrogen or methyl; wherein each R 2  group independently represents an alkyl group having 5 or more carbon atoms; wherein each R 3  group independently represents hydrogen or methyl; wherein each R 4  group independently represents an alkyl group having between 1 and 4 carbon atoms; wherein the proportion of units of formula (I) in the ethylene polymer is between 16 and 30 mol %; and wherein the total proportion of units of formula (I) and formula (II) in the ethylene polymer is between 19 and 30 mol %.  
     
   
   
       2 . An additive composition according to  claim 1 , wherein R 2  represents a branched chain alkyl group having 7 to 15 carbon atoms.  
   
   
       3 . An additive composition according to  claim 1 , wherein R 4  represents ethyl or methyl.  
   
   
       4 . An additive composition according to  claim 1 , wherein the at least one polyoxyalkylene compound comprises a polyoxyalkylene ester, a polyoxyalkylene ether, a mixed polyoxyalkylene ester/ether or mixtures thereof.  
   
   
       5 . An additive composition according to  claim 4 , wherein the at least one polyoxyalkylene compound contains at least one C 10  to C 30  linear alkyl group and a polyoxyalkylene glycol group of molecular weight up to 5,000, the alkyl group in said polyoxyalkylene glycol containing from 1 to 4 carbon atoms.  
   
   
       6 . An additive composition according to  claim 4 , wherein the polyoxyalkylene glycol group has a molecular weight of from 2,000 to 5,000  
   
   
       7 . An additive composition according to  claim 1 , further comprising at least one comb polymer.  
   
   
       8 . An additive composition according to  claim 7 , wherein the at least one comb polymer comprises a copolymer of at least one alkyl fumarate in which the alkyl groups have from 10 to 20 carbon atoms, and vinyl acetate.  
   
   
       9 . An additive composition according to  claim 8 , wherein said the alkyl groups of said vinyl acetate have 12 carbon atoms or said alkyl groups comprise a mixture of C 12 /C 14  alkyl groups.  
   
   
       10 . An additive concentrate composition comprising the additive composition according to  claim 1  and a mutually compatible solvent therefor.  
   
   
       11 . An oil composition comprising an oil and a minor amount of an additive composition according to  claim 1 .  
   
   
       12 . A method for improving the low temperature properties of an oil, the method comprising the addition of an additive composition according to  claim 1 .  
   
   
       13 . A method according to  claim 12 , wherein the oil comprises a fuel oil having a FBP-90% distillation of 30° C. or less and an FBP of 370° C. or less.